Timers are used in a variety of applications and products. Some timers, such as cooking timers are count-down times. Other timers, such as stop-watches are elapsed-time or count-up timers.
Many food items may be considered perishable, such as by having a finite life before spoilage. The length time before food perishes may vary with different climate environments. Dairy products, for example have a limited shelf life at room temperature conditions. But if refrigerated, dairy products may last for days, and perhaps even weeks. Some dairy products, such as cheese, milk, or butter, may be frozen. Frozen dairy products may have a long shelf life before spoiling. Spoilage of dairy products represent a temporal hazard that varies with environmental conditions.